1. Field
Example embodiments relate to systems and methods of applying a material, for example, asphalt, to a surface.
2. Description of the Related Art
FIG. 1A is a view of a system 5 used for applying asphalt to a road. As shown in FIG. 1A, the system 5 includes a dump truck 10, a material transfer vehicle 50, and a paver 90. In the conventional art, the material transfer vehicle 50 includes a hopper 55, a first feeder 60, a second feeder 65, and a third feeder 70. The hopper 55 is configured to receive asphalt from the dump truck 10 and the first feeder 60 is configured to move the asphalt to the second feeder 65. The second feeder 65 includes an auger system to mix the asphalt and feed the asphalt to the third feeder 70 which, in turn, is configured to move the asphalt to the paver 90.
FIG. 1B is a partial schematic view of the material transfer vehicle 50. As shown in FIG. 1B, the material transfer vehicle 50 includes a first electronically controlled hydrostatic pump configured to drive a first hydraulic drive motor which in turn is configured to drive the first feeder 60, a second electronically controlled hydrostatic pump configured to drive a second hydraulic drive motor which in turn is configured to drive the second feeder 65, and a third electronically controlled hydrostatic pump configured to drive a third hydraulic drive motor which in turn is configured to drive the third feeder 70. In the conventional art the first feeder 60 may be controlled by a user input whereas the second and third feeders 65 and 70 receive a fixed signal so that they operate at a relatively high speed.
In the system 5 of FIG. 1A the first feeder 60 includes a chain 72 driven by a sprocket which is driven by a hydraulic motor. FIG. 2, for example, is a partial view of the chain 72. The chain 72 resembles a belt with paddles and/or slats 75 used to move the asphalt 80 along the first feeder 60. Similarly, the third feeder 70 includes a chain which also resembles a belt with paddles and/or slats.
FIG. 3A is a view of another system 100 used for applying asphalt to a road. As shown in FIG. 3A, the system 100 includes a dump truck 110, a material transfer vehicle 150, and a paver 190. In this conventional system 100 the material transfer vehicle 150 includes a first hopper 155, a first feeder 160, a second hopper 157, a second feeder 165, and a third feeder 170. The first hopper 155 is configured to receive asphalt from the dump truck 110 and the first feeder 160 is configured to move the asphalt to the second hopper 157 where it is transferred, via the second feeder 165, to the third feeder 170. The third feeder 170, in turn, moves the asphalt to the paver 190. In this system 100, the first, second, and third feeders 160, 165, and 170 include chains driven by hydraulic motors. The chains, for example, resemble belts with paddles and/or slats as was previously described.
FIG. 3B is a partial schematic view of the material transfer vehicle 150. As shown in FIG. 3B, the material transfer vehicle 150 includes a first electronically controlled hydrostatic pump configured to drive a first hydraulic drive motor which in turn is configured to drive the first feeder 160, a second electronically controlled hydrostatic pump configured to drive a second hydraulic drive motor which in turn is configured to drive the second feeder 165, and a third electronically controlled hydrostatic pump configured to drive a third hydraulic drive motor which in turn is configured to drive the third feeder 170. In the conventional the first and second feeders 160 and 165 are controlled by user inputs and the third feeder 170 is configured to receive a fixed signal which causes it to operate at a relatively high speed.
In each of the above described systems 5 and 100, hydraulic motors are used to control the operations of the first feeders 60 and 160, the second feeders 65 and 165, and the third feeders 70 and 170. In general, the first, second, and third feeders 60 and 160, 65 and 165, and 70 and 170 are independently controlled. In normal operation, the second feeder 65 and the third feeders 70 and 170 are set to deliver asphalt at a relatively high rate regardless of the setting of the first feeders 60 and 160 or the second feeder 165. This manner of controlling the systems 5 and 100 prevents asphalt delivered from the first feeders 60 and 160 to the second feeders 65 and 165 (and then to the third feeders 70 and 170) from over-accumulating in the material transfer vehicle.